Agent Script Testing

My marketing department has come up with a real challenge for me and I'm hoping someone here can help me figure out a way to do this. Currently we populate the browser in CAD with scripts for the agents based on the toll free number that was dialed by the customer. This is done through actions in Cisco Desktop Administrator where the action looks for the DNIS and pushes a web page to the CAD browser. Now, marketing would like to test two versions of the same script on the same toll free number. Ideally, they would like every other call to get different version of the script. For example: Call 1, script 1, call 2 script 2, call 3, script 1, call 4, script 2...you get the idea. Does anyone have any ideas on how to accomplish this? I have heard it done in other call centers by doing it based on odd/even minutes...like 10:00, script 1, 10:01, script 2. This would also be acceptable. Any help or ideas would be greatly appreciated.